The purpose of the present study is to determine the role of protein binding of metabolites of the azo dye hepatocarcinogens, N,N-dimethyl-4-aminoazobenzene (DAB) and 3 feet methyl DAB in their secretion into bile and blood which are excretory pathways and their translocation into the liver cell nucleus where they exert their carcinogenic action. The specific aims are to: (1) determine whether the liver retains specific metabolites of azo dyes which are not secreted into bile and blood and if these metabolites are translocated into the nucleus; (2) identify the noncovalently bound azo dye metabolites associated with the four protein peaks obtained by column chromatography of liver cytosol; (3) purify, characterize and determine the origin of the 70K and 25K azo dye binding proteins in bile; (4) determine if association of metabolites with proteins in liver is important in their secretion from liver into bile; (5) purify and characterize the 88K azo dye binding protein in liver involved in translocation of azo dye metabolites from liver cytosol into the nucleus.